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Document Preservation
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A JewishGen InfoFile
{An article from "Mass-Pocha", the Newsletter of the Jewish
Genealogical Society of Greater Boston, I:2 (Spring 1992)}.
By Warren Blatt
The preservation of genealogical materials was the topic of our
January 19th program at the Newton JCC. Our speaker was Mary Beth
Nelligan of the Northeast Document Conservation Center (NEDCC).
Mary Beth is a preservation professional, who has been doing paper
preservation for three years. The Northeast Document Conservation
Center is a regional non-profit association, founded in 1973, to serve
libraries in the New England states. It provides services for
libraries, historical societies, museums, and individuals. It provides
preservation workshops. Its laboratory helps preserve and restore
documents, maps, wallpaper, as well as unusual items such as tickets and
globes. NEDCC is funded by the National Endowment for the Humanities
(NEH), and also provides outreach and education services.
PAPER. Most paper produced in America before 1860 was made of rag
fiber (cotton or linen), and was produced in a slow, laborious process.
During the 1840's, due to the advancement of the printing press, large
quantities of paper were needed. A new quicker process for paper
production was developed, using wood pulp. Wood pulp contains lignin,
which deteriorates, producing small amounts of hydrochloric acid, which
causes paper to self-destruct after a number of years. This type of
paper becomes brittle and fragile. Most paper produced in the U.S.
since 1860 uses a wood pulp base. Two sample sheets of paper were
passed around the room -- a sheet from 1830 was still white and pliable,
while a sheet from 1924 was yellowed and brittle.
Several mass de-acidification programs have been tested by the
Library of Congress. This process stops deterioration by providing an
alkaline buffer, but it does not correct previous deterioration.
Therefore, this process does not help older brittle materials. The only
hope for preserving these materials is photo reproduction of some type:
microfilming, archival photocopying, etc. Microfilm properly stored
should last 300-500 years.
About 70% of all paper made in the U.S. today has an alkaline
reading, and therefore doesn't have an acid problem. A higher
percentage of European (especially East European) paper is still acidic.
Paper producers need to be refitted to make alkaline paper. The pH
scale measures acidity, on a scale of 0 to 14, with 7 being neutral.
Wood pulp based paper is acidic, and can have a pH reading as low as
4.5. The American National Standards Insti tute (ANSI) recommends a pH
of 8.5 for permanent durable paper.
Handling. Provide a good document environment -- low humidity, low
temperature. Otherwise, catalysts cause deteriora tion more rapidly.
When storing documents in your home or office, be sure that the location
is air conditioned during the summer, when the humidity is high. An
ideal temperature is below 68øF, with humidity below 50% (ideally 35%),
year round. Temperature fluctuations stress paper's bonds. Basements
(too damp) and attics (too hot) are very bad places to store documents.
An interior closet is much better. If you have to, get a room
de-humidifier. Air conditioners also act as de-humidifiers.
One method you can use to help preserve documents is the
"encapsulation technique" -- seal all four edges of a document in a
Mylar capsule. Encapsulation uses 2 pieces of Mylar, sealed with 3M
double-sided tape on all 4 sides. This allows the document to be
handled, with both sides visible. Mylar (Type D) from Dupont is a
stable plastic. However, if the paper is already acidic, sealing the
document causes the rate of deterioration to increase. Don't use scotch
tape on documents -- the adhesive will eventually deteriorate and
discolor. You can use a wheat-starch paste.
PHOTOGRAPHS. Older photographs are usually printed on good quality
paper, but often the backings are acidic, causing deterioration. The
backings on older mounted photographs should be removed, with steam or
by careful application of moisture, and a fair amount of manual
scraping.
Magnetic photo albums -- The adhesive is damaging to photos. The
photos will eventually stick, due to humidity. PVC plastics (polyvinyl
chloride) give off hydrochloric acid, which is damaging to photographs.
Several vendors, listed below, sell albums with Mylar (or polyethylene)
sleeves.
Light causes fading, especially ultraviolet (UV) light. Don't
exhibit materials in direct daylight; use an interior wall. Color
photographs especially fade. When handling materials, especially
photographs, always use clean hands, to avoid leaving deposits of oil.
Label photos with a soft lead pencil, not ink.
Photographic negatives should be stored in low-lignin envelopes.
Discard the envelopes in which they are returned. Photographs should be
framed using archival quality materials. The glass shouldn't touch the
photo; leave some space. Use a window matte to lift the glass. Black
and white photos are more stable than color photos. You can use a color
laser copier (available at most copy centers; prices are usually under a
dollar per exposure) to copy color photographs onto alkaline paper.
Unfortunately, the word "archival" is a meaningless commercial
term, which can mean anywhere from 3 to 500 years. Beware of this label.
Look for: low lignin papers, that are alkaline or have a neutral pH (7.0
or above). You can test a paper's acidity using a litmus kit, or a pH
pen, available from the vendors listed below.
Safe materials for storage include polyester (e.g. Mylar D or ICI
Melinex #516), polypropeylene, polyethylene, Tyvek and triacetate.
Unsafe materials include glassline envelopes, polyvinyl chloride (PVC),
magnetic photo pages, kraft envelopes, and cardboard boxes.
MAGNETIC MATERIALS. Cassette and video tapes typically have a ten
year lifespan, even those labelled "archival". Film is more stable than
video. Several labs do film-to-film and video-to-film transfers. Early
commercial film was nitrate based; new film is polyester or acetate
based. Store film in the same environment as you would paper: low
temperature, low humidity. Remove film from cardboard boxes, which may
be acidic. Use metal canisters and metal shelving. Audio and video
tapes suffer from disintegration of magnetization. Reel-to-reel tape is
more stable the cassettes.
CONSERVATION AT NEDCC. Mary Beth concluded her presentation with a
slide show. Conservation techniques include leaf-casting, which forms
new paper to fill in spaces in old paper. This requires very
specialized equipment. Other services provided by NEDCC include a
bookbindery, photographic copying, and microfilming services.
All conservation treatments should be reversible, in case current
methods are later proven to be harmful, or if later technology finds
better methods of preservation. This is part of the conservator's code
of ethics.
For help or advice on preserving your own materials, you can
contact the NEDCC at 100 Brickstone Square, Andover, MA 01810-1494,
(978) 470-1010, ; or The American Institute
for Conservation, 1717 K Street NW, Suite 200, Washington, DC 20006,
(202) 452-9545, , a professional organization
for conservators. They can give references to professional conservators.
VENDORS:
Light Impressions
P.O. Box 940
Rochester, NY 14603-0940
1-800-828-6216
University Products, Inc.
517 Main Street
P.O. Box 101
Holyoke, MA 01041-0101
1-800-762-1165
The Preservation Emporium
P.O. Box 226309
Dallas, TX 75222-6309
(214) 331-8902
WEB RESOURCES:
* Northeast Document Conservation Center (NEDCC)
"Preservation 101" online course
* Northeast Document Conservation Center (NEDCC)
"Preservation of Library & Archival Materials: A Manual"
* The American Museum of Photography
Preserving & Protecting Photographs: A Buyer's Guide
* Light Impressions
Frequently Asked Technical Questions and Glossary
* Conservation OnLine
Resources for Conservation Professionals
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